Based on in situ and ground‐based observations, a new type of “polar cap hot patch” has been identified that is different from the classical polar cap enhanced density structure (cold patches). ...Comparing with the classical polar cap patches, which are transported from the dayside sunlit region with dense and cold plasma, the polar cap hot patches are associated with particle precipitations (therefore field‐aligned currents), ion upflows, and flow shears. The hot patches may have the same order of density enhancement as classical patches in the topside ionosphere, suggesting that the hot patches may be produced by transported photoionization plasma into flow channels. Within the flow channels, the hot patches have low‐energy particle precipitation and/or ion upflows associated with field‐aligned currents and flow shears. Corresponding Global Navigation Satellite System (GNSS) signal scintillation measurements indicate that hot patches may produce slightly stronger radio signal scintillation in the polar cap region than classical patches. A new type of polar cap patches, “polar cap hot patches,” is identified to differentiate enhanced density structures from classical patches. Hot patches are associated with particle precipitations, ion upflows, field‐aligned currents, and shear flows in the polar cap. Hot patches may lead to slightly stronger ionospheric scintillations of GNSS signals in the polar cap region than classical patches.
Key Points
A new type of polar cap patches, “polar cap hot patches,” is identified to differentiate enhanced density structures from classical patches
Hot patches are associated with particle precipitations, ion upflows, field‐aligned currents, and shear flows in the polar cap
Hot patches may lead to slightly stronger ionospheric scintillations of GNSS signals in the polar cap region than classical patches
Tracking the formation and full evolution of polar cap ionization patches in the polar ionosphere, we directly observe the full Dungey convection cycle for southward interplanetary magnetic field ...(IMF) conditions. This enables us to study how the Dungey cycle influences the patches' evolution. The patches were initially segmented from the dayside storm enhanced density plume at the equatorward edge of the cusp, by the expansion and contraction of the polar cap boundary due to pulsed dayside magnetopause reconnection, as indicated by in situ Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations. Convection led to the patches entering the polar cap and being transported antisunward, while being continuously monitored by the globally distributed arrays of GPS receivers and Super Dual Auroral Radar Network radars. Changes in convection over time resulted in the patches following a range of trajectories, each of which differed somewhat from the classical twin‐cell convection streamlines. Pulsed nightside reconnection, occurring as part of the magnetospheric substorm cycle, modulated the exit of the patches from the polar cap, as confirmed by coordinated observations of the magnetometer at Tromsø and European Incoherent Scatter Tromsø UHF radar. After exiting the polar cap, the patches broke up into a number of plasma blobs and returned sunward in the auroral return flow of the dawn and/or dusk convection cell. The full circulation time was about 3 h.
Key Points
Direct observations of the full Dungey cycle by tracking polar cap patches
Formation and evolution of patches modulated by dayside and nightside reconnections
The full circulation time was about 3 h
Leptomeningeal metastases (LM) are more frequent in non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. Due to limited access to leptomeningeal lesions, the ...purpose of this study was to explore the potential role of cerebrospinal fluid (CSF) as a source of liquid biopsy in patients with LM.
Primary tumor, CSF, and plasma in NSCLC with LM were tested by next-generation sequencing. In total, 45 patients with suspected LM underwent lumbar puncture, and those with EGFR mutations diagnosed with LM were enrolled.
A total of 28 patients were enrolled in this cohort; CSF and plasma were available in 26 patients, respectively. Driver genes were detected in 100% (26/26), 84.6% (22/26), and 73.1% (19/26) of samples comprising CSF cell-free DNA (cfDNA), CSF precipitates, and plasma, respectively; 92.3% (24/26) of patients had much higher allele fractions in CSF cfDNA than the other two media. Unique genetic profiles were captured in CSF cfDNA compared with those in plasma and primary tissue. Multiple copy number variations (CNVs) were mainly identified in CSF cfDNA, and MET copy number gain identified in 47.8% (11/23) of patients was the most frequent one, while other CNVs included ERBB2, KRAS, ALK, and MYC. Moreover, loss of heterozygosity (LOH) of TP53 was identified in 73.1% (19/26) CSF cfDNA, which was much higher than that in plasma (2/26, 7.7%; P<0.001). There was a trend towards a higher frequency of concomitant resistance mutations in patients with TP53 LOH than those without (70.6% versus 33.3%; P=0.162). EGFR T790M was identified in CSF cfDNA of 30.4% (7/23) of patients who experienced TKI progression.
CSF cfDNA could reveal the unique genetic profiles of LM and should be considered as the most representative liquid biopsy medium for LM in EGFR-mutant NSCLC.
Although magnesium alloys, as the lightest structural alloys, offer significant potential for automotive applications, their applications remain limited due to their poor formability at room ...temperature. Since the strategies used for improving formability usually result in a degradation of strength, there are no high strength magnesium alloys showing good formability. Here we report an alloy design concept that can simultaneously provide high strength and good formability. Such designed alloy when subjected to an appropriate processing technique shows a combination of strength and formability that surpasses those of the existing magnesium alloys reported so far. The alloy design concept used in the present study is based on the utilization of alloying elements that can induce precipitation, as well as maximize the segregation of other texture-controlling alloying elements. Such developed alloy is expected to broaden the application of Mg alloy sheets, which are now starting to gain acceptance by automotive industries.
Two types of poleward moving plasma concentration enhancements (PMPCEs) were observed during a sequence of pulsed reconnection events, both in the morning convection cell: Type L (low density) was ...associated with a cusp flow channel and seems likely to have been produced by ionization associated with particle precipitation, while Type H (high density) appeared to originate from the segmentation of the tongue of ionization by the processes which produced the Type L events. As a result, the Type L and Type H PMPCEs were interspersed, producing a complex density structure which underlines the importance of cusp flow channels as a mechanism for segmenting and structuring electron density in the cusp and shows the necessity of differentiating between at least two classes of electron density patches.
Key Points
First observed TOI patches in the morning cell
Differentiating between at least two classes of electron density patches
TOI patches segmented by flow channels with precipitation electrons
Summary
Dexmedetomidine might reduce delirium after cardiac surgery. We allocated 326 participants to an infusion of dexmedetomidine at a rate of 0.6 μg kg−1 for 10 min and then at 0.4 μg.kg−1.h−1 ...until the end of surgery; 326 control participants received comparable volumes of saline. We detected delirium in 98/652 (15%) participants during the first seven postoperative days: 47/326 after dexmedetomidine vs. 51/326 after placebo, p = 0.62, adjusted relative risk (95%CI) 0.86 (0.56–1.33), p = 0.51. Postoperative renal impairment (Kidney Disease Improving Global Outcomes stages 1, 2 and 3) was detected in 46, 9 and 2 participants after dexmedetomidine and 25, 7 and 4 control participants, p = 0.040. Intra‐operative dexmedetomidine infusion did not reduce the incidence of delirium after cardiac valve surgery but might impair renal function.
Abstract The aim of this study was to identify the risk factors for free flap failure after head and neck reconstructive surgery. The data of 881 consecutive patients who underwent free flap surgery ...at the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, between January 2013 and November 2016, were reviewed retrospectively. All surgeries were performed by a single head and neck surgical team. Patient demographic and surgical data that may have an influence on free flap outcomes were recorded. The χ2 test and multivariate logistic regression analysis were used to identify relevant risk factors. In total, 881 free tissue transfer surgeries were included in this study. Free flap failure occurred in 26 of 881 flaps (2.9%). A history of irradiation (odds ratio 0.205, 95% confidence interval 0.07–0.56; P = 0.002) was a statistically significant risk factor for free flap failure. Age, diabetes mellitus, history of previous neck surgery to the anastomosis side, donor site, choice of recipient vein, use of a coupler device, and postoperative anticoagulation were not associated with free flap outcomes. Thus, it is concluded that when performing head and neck reconstructive surgery, special attention should be paid to patients who have previously undergone irradiation.
Adsorption is one of the most widely applied techniques for environmental remediation. Its kinetics are of great significance to evaluate the performance of a given adsorbent and gain insight into ...the underlying mechanisms. There are lots of references available concerning adsorption kinetics, and several mathematic models have been developed to describe adsorption reaction and diffusion processes. However, these models were frequently employed to fit the kinetic data in an unsuitable or improper manner. This is mainly because the boundary conditions of the associated models were, to a considerable extent, ignored for data modeling. Here we reviewed several widely-used adsorption kinetic models and paid more attention to their boundary conditions. We believe that the review is of certain significance and improvement for adsorption kinetic modeling.
Metal-organic frameworks (MOFs) have so far been highlighted for their potential roles in catalysis, gas storage and separation. However, the realization of high electrical conductivity (>10
S cm
) ...and magnetic ordering in MOFs will afford them new functions for spintronics, which remains relatively unexplored. Here, we demonstrate the synthesis of a two-dimensional MOF by solvothermal methods using perthiolated coronene as a ligand and planar iron-bis(dithiolene) as linkages enabling a full π-d conjugation. This 2D MOF exhibits a high electrical conductivity of ~10 S cm
at 300 K, which decreases upon cooling, suggesting a typical semiconductor nature. Magnetization and
Fe Mössbauer experiments reveal the evolution of ferromagnetism within nanoscale magnetic clusters below 20 K, thus evidencing exchange interactions between the intermediate spin S = 3/2 iron(III) centers via the delocalized π electrons. Our results illustrate that conjugated 2D MOFs have potential as ferromagnetic semiconductors for application in spintronics.
Abstract Background and objective The survival outcomes of patients with metastatic nasopharyngeal carcinoma (NPC) differ significantly between individuals. This study aimed to evaluate whether serum ...lactic dehydrogenase (S-LDH) level had a clinical value in predicting clinical response and survival outcome for patients with metastatic NPC. Methods S-LDH level was measured at baseline and then before every cycle of treatment in 689 NPC patients with distant metastases. Correlations of pre-treatment and post-treatment S-LDH levels to response of treatment and survival were analysed retrospectively. Results Patients with elevated values of pre-treatment S-LDH (>245 IU/L) had significantly worse survival than those with normal values of pre-treatment S-LDH (⩽245 IU/L) ( P < 0.001). Patients with elevated values of post-treatment S-LDH had worse survival compared with those with normal values of post-treatment S-LDH ( P < 0.001). Patients with normal values of pre-treatment and post-treatment S-LDH showed the highest response rate and the most favourable prognosis. Conclusion S-LDH appears to be a significant independent prognostic index in patients with disseminated NPC that should be considered in the comparison of the results achieved with different therapies and in planning new randomised clinical therapeutic trials.
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